Sun protection and chronic illnesses: How to stay safe in the sun

How do sunscreens work, and what do SPF ratings mean?

Sunscreens are designed to shield the skin from harmful ultraviolet (UV) rays. There are two primary types of UV radiation:

• UVB rays, which cause sunburn and superficial skin damage
• UVA rays, which penetrate deeper into the skin, contributing to premature ageing and increasing the risk of skin cancer

What is SPF?

SPF, or Sun Protection Factor, measures a sunscreen's ability to block UVB rays. For example, SPF 30 filters out about 96% of UVB rays and SPF 50 filters around 98%.

However, SPF does not mean you can stay in the sun longer without risk. Sunscreen should be reapplied every two hours, regardless of SPF level.

To ensure full protection, always choose a broad-spectrum sunscreen that guards against both UVA and UVB rays. UVA rays can pass through glass and clouds, and they are not covered by the SPF rating alone.

What types of filters are in sunscreen?

Sunscreens use one or both of the following:

• Chemical (organic) filters: absorb UV rays and convert them into heat
• Mineral (physical) filters: reflect UV rays away from the skin, using ingredients like zinc oxide or titanium dioxide

Mineral sunscreens are often recommended for sensitive skin, as they’re less likely to cause irritation.

Why is sun protection especially important for people with chronic conditions?

If you live with a chronic illness, such as lupus, psoriasis, cancer, or autoimmune diseases, your skin may be more sensitive to sunlight.

In these cases, sun protection becomes a medical necessity. Even brief exposure can lead to severe sunburn, rashes, blistering, and intense itching or trigger flare-ups (especially in lupus)

Some medications also make the skin more vulnerable, such as immunosuppressants, which weaken your skin’s defences, chemotherapy and radiation, which thin the skin, and photosensitizing drugs (e.g. retinoids, certain antibiotics), which can cause pigment changes or irritation.

Because of these risks, dermatologists advise using high-SPF, broad-spectrum sunscreens (SPF 50 or higher), applying them generously and often, and reinforcing protection with wide-brimmed hats, UV-protective sunglasses, and long-sleeved clothing or UV-resistant fabrics. It is also advised to avoid sun exposure between 12 pm and 4 pm, when rays are strongest.

Always consult your doctor or dermatologist to choose the right sunscreen for your skin condition and treatment plan.

How to choose sunscreen for sensitive or compromised skin

Not all sunscreens are created equal. When your skin is already fragile, selecting the right formula is crucial.

Prioritize high SPF

For maximum protection, select SPF 50 or higher. If your skin is highly vulnerable, avoid anything below SPF 30, as it may not offer sufficient defence.

Look for “broad-spectrum” or “UVA/UVB” coverage

This ensures your sunscreen protects against both types of UV radiation, which is vital for preventing further skin damage or aggravating chronic conditions.

Choose mineral filters

Mineral-based sunscreens (with zinc oxide or titanium dioxide) are ideal for delicate or damaged skin. They begin working immediately and are less likely to cause allergic reactions.

Pick gentle, hypoallergenic formulas

Fragrance-free, non-comedogenic, and hypoallergenic sunscreens reduce the risk of irritation. Look for products tested by dermatologists (and paediatricians for children) for added reassurance.

Check the ingredients

Avoid potential irritants such as:

• Fragrances
• Alcohol
• Parabens
• Harsh preservatives

If you’ll be swimming or sweating, make sure the sunscreen is water- and sweat-resistant.

Trust certified quality labels

Many reliable brands, especially those sold in pharmacies or recommended by dermatologists, offer sunscreens formulated specifically for sensitive skin. Look for quality certifications and read product reviews for reassurance.

How should you apply and store sunscreen?

Even the best sunscreen won’t work if it’s used incorrectly. To ensure full protection:

Apply enough

Most people don’t use enough sunscreen. As a guide, use ½ to 1 teaspoon for your face and neck and about 30 ml (roughly a shot glass or three tablespoons) for your body. Don’t forget areas like ears, back of the neck, tops of shoulders and feet, and the backs of hands.

Apply at the right time, and reapply!

Put sunscreen on 20–30 minutes before going outdoors. Reapply every two hours, and always after swimming, sweating, or towel-drying.

TIP: Even if you don’t feel sunburned, UV rays are still penetrating your skin. Always reapply regardless of how your skin feels.

Store it properly

Keep your sunscreen in a cool, dry place, away from direct sunlight. Always check the expiration date, expired sunscreen can lose its effectiveness and won’t protect you as promised.

Key takeaways

If you have a chronic illness or sensitive skin, sun protection is more than just comfort, it's a crucial part of managing your health. With the right sunscreen and protective habits, you don’t have to avoid the outdoors.

Remember to:

• Use high-SPF, broad-spectrum sunscreen
• Choose mineral-based, hypoallergenic formulas
• Apply generously and often
• Wear protective clothing and accessories
• Avoid peak sun hours and consult your healthcare provider for tailored advice

With a little preparation and the right products, you can enjoy sunny days safely, without putting your skin at risk.

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